Machine for grinding crankshafts



Nov. 12, 1940. H, S. INDGE MACHINE FOR'QRINDING CRANKSHAFTS Filed Nov. 26, 1938 4 sheds-'sheet 2 Nov. l2, 1940.- H. s.l INDGE u l MACHINE Fon GRINDING `CMNKSMFTS Filed Nov. 2e, 1938 4 sheets-sheet s Nov. 12, 1940. H s INDGEl MACHINE FOR GRINDING CRANKSHAFTS yFiled Nov. 26, 1938 4 Sheets-Sheet 4 22a-h# of 25253@ Witmss e wenn Patented Nov. 12, 1940 Norton Company, Worcester,

tion of Massachusetts Mass., acorpora- Application November 2s, 193s, serial 242,444 Y v.12 claims. (ci. "s1-rain' j This invention relates to a' machine for grind- `1k ing crankshafts, and more particularly to a machine which will serve to grind or polish'several crankshaft pins simultaneously.

. The crankshafts as Yuse'cl in automotive engines have four or more crank pins which are` oil'set` relative to the centralbearing axis of the crankshaft. These pins must be ground tol extremely accurate dimensions land polished surfaces be- 'cause of the rigid requirements of the automotive vindustry. Owing tothe number and arrangement of the pins on the shaft, it isa slow and expensive operation to grind each `one, of

y these pins to the Arequiredl surface, vand it is,

therefore, desirable to provide 1a mechanism which willgrind all'of the pins at the same time, asY well as to shape each. cranknpln' by means of a positively rotated grinding wheel throughout its entire which will true they pin length.

It is, therefore, a primary objectfoi this invention to provide a machine which will grind a plurality and preferably all of the crank pins of a shaft simultaneously.

A further object is to provide 'a machine offthis type in' which the pins are ground by wheels so arranged thatvthey will grind throughout the full length of pinsofdifferent lengths. A

A further -object is to provideL a machine in which yeach pin is ground independentlyzof the others by a grinding 'wheel so mounted and arranged that it may be adjusted towards and from the work independently of thefjother wheels. Another'object is to provide a crank pin grinding machine in which each pin is ground'by a rotating grinding wheel whichis held always in correct relation with its associated pin as the latter is revolved.

A still further object isto provide a crankshaft grinding machine in which the grinding wheels for `the. different pins are separately mounted and yet are moved in unison and in timed relationship with the revolving crankshaft in such a manner that the flat side of each wheel maintains abrading contact withits pin as the wheel and the pin revolve.` Further objects will be apparent in the following disclosure.

Referring to the'drawinga whichl illustrate one embodiment of the invention:v

Fig. 1 is a partial front elevation ofthe machine with acrankshaft mounted inplace for the polishing operation;

Fig.` 2 is a vertical-section on the line 2--2 `of Fig. 1, parts being shownin full outline and other parts broken away;

. driving mechanism; 1 Fig. 4is asection on'the line `ii---B of Fig. 2 showing Fig. 3 is a fragmentary vertical section taken onvthe line '3-3 "of Figi-1 showing the head stock y line 4---4 of Fig.-3, "showing the crankshaft' supporting and driving Fig. 5'is` afront elevation of the'tailstock partlyin sectionr" .f f f Fig. 6 is., a`jfragmentary plan viewv of the machine with-parts-removed for l clarity; f

Fig.` 7 is' asection'al view of` the grinding -wheel spindle supporting and driving niechanisxn;I

Fig. 8 is a `fragmentary sectional view on the one-of the master crankshafts;

rig. 9 1s enencview of the abrasive wheel f and its support looking inthe directionof the arrow l9 in Fig. '7 showing/the abrasivewheel concentric with -the axis oil-its drivingmember; f u v Fig. 10 is wheel adjusted to an eccentric'position; r

Fig. 1'1 is an end view on the line Ilof Fig. 7, withthe cover removed; 5 l Fig. y12.is a similar view on the liney I2-42 of mais is e. view` similar tf1-Fig'. 12l snowing the grinding shaft in an eccentric-position; and Fig. 14 is a fragmentarysectionalvieW- onthe Aline 'i4-I4 of Fig. 2 showing the path-of movement of the grinding wheel relative 'to the work. Y

In accordance with this invention, I have provided a machine for grinding' or polishing a crankshaft, which comprises a grinding/wheel mountedito grind a pinfwhile the latter rotates and revolves relative to the axis of the shaft. It

` preferablyV has a setfof independently movable mounts arranged to holdvthe flat endslof abrasive wheels in contact with, associated pins .on the shaft as the latter revolve. l Eachwheel may bel mounted eccentrically onasupporting spindle, randthe .Wheel .may be smaller in diameter than the length ofthe crank pin;the parts'beingso arranged that the abrasive ofthe VWheel may-travel in a planetarypath and sol grind the length ofthe pin as it rotates fand'revolves. This eccentricity of the wheel axis may be adjusted, if desired, so as to permit grinding crank pins ofdiiferent lengthsl The abrasive wheels kare each preferably driven by means of an independent motor directly connected to its spindle'.` The mounts for the grindingA wheelspinfollow its associated pin on the revolving cranka similar view showing the grinding Y shaft and maintain abrading contact therewith. The wheel mounts may also be so arranged that they may be moved away from the work, as by means of fluid pressure mechanism, to permit replacement of the crankshaft being ground. Each wheel may also be independently adjusted toward and from the work, and the parts are preferably so arranged that each wheel will be held under resilient pressure against the work.

All of these various features are shown combined in the mechanism illustrated in the drawings. As there shown, the base I of the machine carries a head stock II and tailstock I2 on which the crankshaft work piece I4 is suitably mounted. Each pin I5 of the crankshaft is adapted to be ground or polished by means of a separate wheel I8, which in the present embodiment, is shown asa cup shaped wheel removably mounted on the end of a wheel spindle I8. i

As shown particularly in Fig. '1, the wheel spindle I8 is mounted for rotation within a rotatable tube 28, and it is driven by power mechanism, such as an electric motor 22 of suitable construction which is xedly mounted on the stationary housing. The shaft 23 of the motor is removably connected with the spindle I8 through a telescoping jointcomprising a pin 24 on the motor shaft 23 riding in a slot 25 in the hollow telescoping end 26 of the :spindle I8. This permits-adjustment of the wheel spindle towards and from the work.

The housing for the driving mechanism cornprises a cylindrical casing 30 carrying an enlarged portion 3l secured thereto. The casing 30 has bearing members 32 and 33 (Fig. 7) mounted therein, within which the hollow shaft 20 rotates. The spindle I8 is carried on its forward end by a bearing 34 located on the inside of the tapered nose 35 which has a iange 36 vconnected to a flange 31 on the hollow spindle sleeve 20. This construction gives a planetary inotion to the grinding wheel.

The spindle I8 may be adjustably positioned in a desired eccentricity relative tothe axis of the surrounding tube 20, which is widely spaced therefrom lto' fpermit the desired adjustments.

This adjustment is effected by the mechanism shown in Figs. '1, 9 and 10.` 'I'he nose 35 of the housing is mounted to swing about a cap screw 40 which passes freelythrough the flange 36 and is threaded into the flange 31 of the rotatable tube 28. At the upper end of this nose 35 and diametrically opposed to the cap screw 40 is a further cap screw 42 passing freely through an elongated arcuate slot 43 in the flange 36 and this screw is also threaded into the flange 31. Adjustment screws 44 and 45 are threaded into the flange 36, and they are arranged to contact with opposite sides of the upper cap screws 42, so that by separately adjusting these screws 44 and 45, one may swing the nose 35 about its supporting pivot 48 and thus adjust the nose and the grinding wheel spindle carried thereby so that the latter will be in a desired eccentric position relative-to the axis of the hollow shaft 26.

gear 48. The sun gear 48 is carried on a pivot pin 49 fixed in the rings 50 and 5I. 'I'he ring 50 is in turn threaded onto the end of the spindle sleeve and forms a continuation thereof, the two parts being secured ltogether by a set screw. The ring 5I, to which the motor is pinned, has an arcuate slot 52 therein Within which rides the pin 53 projecting from the inner ring 50. These parts correspond in arrangement with the slot and pin shown in Fig. 9 and permit the ring 50 and hollow shaft to swing about the axis of pin 49 and relative to the motor shaft 23 and wheel shaft I8. Two nuts 54 are threaded onto the spindle sleeve 20 and bear against the upper end of the housing and thus hold the sleeve 20 in proper adjusted driving position. A cap 55 is attached as by means of a set screw to the housing so as to protect the gear mechanism from dust.

As the gear 41 is rotated by the motor shaft, it drives the sun gear 48 around the internal ring gear 46 and causes the sun gear to travel in a concentric on planetaryv path relative to the axis of the grinding Wheel spindle. The sun gear is mounted in alignment with the cap screw 40 which serves as a center about which the nose swings; hence, when the grinding wheel shaft I8 .is moved to vary its eccentricity by means of the adjustment members shown in Figs. 9 land 10, the gear 41 will be likewise moved and Will ride around the sun gear 48 and always remain in driving contact therewith. This causes the pin 49, which forms the `bearing support of the sun wheel, to drive the rings. 50 and 5I and the sleeve 20 and force the latter to rotate about its axis. It will now be seen that when the grinding wheel I6 is rotated on its shaft ,I8 by means of the motor 22, the gear mechanism in the housingV will cause the hollow shaft 20 to rotate and. carry the inner grinding wheel shaft I8 in .an eccentric path around the axis of the shaft 20.

As shown particularly in Fig. 14, the grinding wheel I6 is preferably smallerin diameter than the length ofthe crank pin I5.' and the eccentrcity of the wheel axis relative to the axis of the hollow shaft 20 isso adjustedA that as the Wheel rotates it will move back and forth substantiallyvthe, entire distance between the cheeks 51 and 58 of the crank shaft pin, so that the wheel `will grind the entire length of that pin. The eccentric motion of the abrasive body over the work surface causes an abrading action somewhat like the circular motion of a hand honing operation, and the rotation of the wheel prevents an uneven wear thereof and provides a break-up motion. Hence, the combined action of the two motionsproduces a lapped and finely finished surface. 'I'he wheel may have a iiat disk for its end face, but it is preferably cup shaped, since the central portion of the wheel rotates at too slow a rate to be eiiicient in its cutting action. Thus by making proper adjustment of the pressure of the wheel on the work and using suitable abrasive grains and wheel structure, one may obtain a very fine polishing action and not only true but polish a crankshaft and provide a desired finish. y

The grinding wheels may be made of suitable material,- such as crystalline alumina, silicon carbide, boron carbide or diamond grains, bonded by suitable bonds, such as the standard vitrifled ceramic materials, vulcanized rubber, shellac, polymerized resins and heat hardening resinoids of the type of. the phenolic-formaldehyde condensation products. Each vof the wheels may be'suitably shaped, either to present a sharp corner at its periphery or preferably to present a rounded corner,` the radius of which corresponds with the curvature of the llet of the crank pin. If this latter constructionis" adopted, then the grinding wheel may grind the entire length of the pin and tothe cheek of the crankshaft and at the same time nish the 'fillet and leave it in satisfactory shape and condition for use without any further grinding operations.

The grinding, wheels may be held in proper contact with the crankshaft pins asf the latter revolve about the axis of the'crankshaft'bearings by providing'a connection between the work and each wheel which causesl the wheel axis tov travel in synchronism with the work and through a path parallel with that of the pinbeing ground.

This is `preferably effected by means Vof the mechanism, shown in Figs. 2 and 6, comprising two master crankshafts 60 and'62`which -are rotated'in synchronism with thework bein'g'ground.-

These shafts support yand move the various wheel housings 30 as required. To this'end, each housing 30 has a flange 64 (Figs. '7 and 8) projecting downwardly therefrom, which carries a dovetailed portion 65 forming aslide interfittinlg with means of a` common'driving mechanism:y This comprises a rock shaft 90 (Figs. 2 and `6) Ysuitably mounted in bearings onv the baseA |0 ofthe machine. A sleeve 9| rotatable on one end of the shaft carries asprocket S2 which drives through a chain 93 a' sprocket on the end bearing pin of the master crankshaft 60.- A similar'sprocket 94 on the' crankshaft 60 drives a sprocket y98, on the master shaft 62 and these sprocket gears are all of the. same size so that the two master shafts are revolved in synchronism. The master driving sleeve 9| is driven by means of a second sprocket thereon and a chain which in turn is driven by a sprocket |02"fixedA on the head stock spindle |04, to-which the crank shaft |4is re movably affixed for revolution thereby. As shown in Figs. 3 and 4, the head `vstock spindle |04 is mounted in ball bearings |06 and |01 'within thehousing 'I'his spindle also carries. a worm gear` |08 which mesheswith the driving worm |09. This'worm is mounted on Ia `shaft ||0 suitably supported inbearings in thehousing. i., y

A suitable clutch mechanism maybe provided for releasably connecting the worm shaft ||0 with a'driving pulley ||2, :which is driven from a suitable electric motor H4 (Fig. 2)- mounted in the base of the machine, the power drive' being effected by means ofl V-belts |`|5 suitably meshing with the drivingpulley ||2. The clutch mechanism, as shown inFig. 3, comprises a han' die ||6 pivotally mounted toshvft'asliding clutch member 8 keyed on the shaft ||0 which connects through `a suitable friction drive |20 with the `shaft |2|l carrying the driving pulley ||2'.

The friction drive may comprise alternately ar-l ranged disks on the spindle I|0 and rings on the endo: theshaft nl. when me dutch hanand so serve to rotate the shaft H0. A .vsimilarly'arranged -set of (friction disks' |22 at the left may serve as brake elements to'stop vthe driven shaft when theclutch handle is thrown in the opposite direction.l

A handle |30 (Fig. 1) serves to throw a yoke |32 (Fig. 4) in such a-manneias tovthrus't a drivingy piny |34 intothe plate |35 forming the driving element -of the crankshaft I4. Thepin |34 is mounted ona sliding collar |36'slidably keyed to the shaft |04. v'I 'hetailstock for car;- rying the other end ofthe crankshaft comprises anysuitable construction, such ,as apin 200, suitably mounted in the'houlsing. This pin200 may die ||6 is thus moved towards the right, the disks are brought into frictional driving engagement..

be heldin an outward position by al spring 20| located at the rear and within vthe housing so that by thrusting a" crankshaft `against `this centering; pin it'will be pushed back and permit the driving plate at the otherend to be suitably connected to the head stock driving spindle.

,It'will, therefore, be seen that ythe Yelectric motor |4 drives the Pulley I2, this in turnr drives the shaft ||0 andconnected Worm gear to rotate the crankshaftfto be polished in synchronism with the two master crankshafts. The pins on the master crankshafts correspond/ y in .'DoSi/ion y and' arrangement with those on the work, and so each ofthe grinding wheels is held in proper abrading contact with its associated pin.. If

desirecLfthe` mainbearings may also beiground atA the same time, and in that case the support for `its vgrinding wheelV will remain stationary.,

and not revolve. 'I'he differentv grinding wheel mounts are located in different positions at any given time and thus tend to balance each other as they revolve and thus reduce any tendency for `vibration Within the machine. f Each grinding' wheelfmayxbe suitably adjustedy relative tothe' work. A simple device, as'shown loosening this' clamp screw, one may manually movethe parts 4to an adjusted desiredy position and then set the screw again to hold the wheel as thus positioned. The wheel may be held forward' against the work by means of a spring |44 (Fig. '1) which surrounds the shaft I8 and engages a'shoulderv |46 on the nose'35 anda pinl |48 rpassed through the spindle |84. 'I'his spring, being underl compression, tendsto thrust the grinding wheel forward to a required dis-v tance which may be limited by the "amount of movement' permitted by the pin |48 engaging the rear of the bearing 34. This causesthe grinding wheel to engage the work'with a resilient pressure and thus to take 111;). for wheel and work wear and toadjustfor improper positioning of the housing on its mount 61. A micrometer mechanism may be employed to position the Wheel accurately relative to the w'ork. As'shownv in Fig. 7,-this may'comprise a screw |45 threadings, which are carried on their respective mounts 61, may be simultaneously moved by a power mechanism. To that end, the master crankshafts are supported on uprights |50 and |52 (Fig. 2) carried on a plate |54 having downwardly projecting arms |60 fixed on and mounted to swing with the rock shaft 90. These uprights carry half bearings |56 and |51, and suitable bearing caps |58 and |59 are provided to secure the main bearings of the master crankshafts to this swinging mount.

This mounting plate |54 may be moved by hand or by power, such as the uid pressure mechanism, shown particularly in Fig. 2. To this end, a rock arm |62 is xed on the rock shaft 90 and crooked around to pivotally connect with a pitman |64V which is attached to and moved by the pistonk |65 .mou'nted within the piston chamber |66 which is in turn pivotally mounted at |68 on a lug projecting from the inner base of the casing |0. Fluid under pressure, such as oil, may be sent to opposite sides of the piston by means of suitable hose connections |10 and |1| connected with a manually adjustable valve |12 comprising three pistons |13, |14 and |15 on a piston rod |16 which is suitably controlled by a hand operated lever |11. Fluid is forced under pressure from a pump |18 through a pipe line |19 which connects only with the central portion of the valve casing and beneath the valve piston |14 when the latter is in an inoperative position. The pump may be of any suitable design and connected with a pressure release valve and piping for returning the oil to an oil reservoir |80 provided in the base of the machine. A return pipe line |82 connects through pipes |83 and |84 with ports located opposite pistons |13 and |15 inthe valve casing. Hence, when the valve rod is moved to the left, oil is Isent through the pipe line |10 to move the piston |65 towards the left and the pipe -|1| becomes an exhaust pipe connecting the valve chamber with exit pipe |84. When the valve is moved to the right, the mechanism is similarly arranged to drive the piston to the right. When the piston is moved to the left theplate |54 carrying the wheel housings is elevated to thrpw the wheels back towards the right and out of contact with the work, so that the work may be removed and a new crank shaft and new wheels put into position.

It will be understood that one may employ suitable mechanisms well known in the industry for mounting the various parts and driving the same so as to take care of the different shapes,

one of the wheel mounts and associated parts.v

types and sizes of crankshafts and numerous modifications may be made in the mechanism as required. Also, one may make a simplified machine for grinding a single pin by employing only Various other features above described may be omitted, and numerous changes may be made by substituting equivalent constructions for those herein described. Hence, the above description of akmachine embodying all of the inventive features is to be interpreted as being illustrative of the principles of the invention and not as limitations thereon except as required by the scope of the claims appended hereto.

I claim: v

1. A crankshaft grinding machine comprising means for supportinga crankshaft for rotation about the axis of its bearings, a grinding wheel, means for rotating the wheel, means for revolv- 75 ing it eccentrically relative to its axis of rotation, and means for supporting the at side of the wheel in. abrading contact with the crank pin asthe latter revolves about the crankshaft axis.

2. A crankshaft grinding machine comprising means for supporting a crankshaft for rotation about the vaxis of its bearings, a grinding wheel having its fiat face of smaller diameter than the length of the pin and in abrading contact with an eccentrically mounted crank pin, means for rotating the wheel, means for revolving it eccentrically relative to its axis of rotation as it grinds the pin, and means for holding the wheel in abrading contact with the pin during revolution thereof about the crankshaft axis.

3. A crankshaft grinding machine comprising means for supporting a crankshaft for rotation about the axis of its bearings, a grinding wheel having its end fiat face of shorter diameter than the length of the crank pin and in abrading* contact with the same, means for rotating the wheel and for revolving it eccentrically as it grinds the pin, and means including a master crankshaft for holding the wheel in contact with the work and revolving it in synchronism therewith. e

4. A crankshaft grinding machine comprising means for supporting a crankshaft for rotation about the axis of its bearings, a grinding wheel having its flat face in abrading'contact with an eccentrically revoluble crank pin, a motor connected to rotate the wheel and means driven by said motor for revolving the wheel eccentrically as it grinds the crankshaft.

5. A crankshaft grinding machine comprising means for supporting a crankshaftl for-rotation about the axis of its bearings, a grinding wheel having its at end face in abrading'contact with an eccentrically revoluble crank pin,jafsupport for saidwheehan electric motor on'saidsupport connected to rotate the wheel, means driven by'v said motor for revolving the wheel axis eccen trically and means for holding the wheeliincon-' tact with the pin during revolution of the latter.

6. A crankshaft grinding machine 'comprising n means for supporting a crankshaft for rotation about the axis of its bearings, amaster l crankshaft axially parallel with the work, means for revolving the two crankshafts` in synchrjonism, a grinding wheel mountedl to grind on itslat end face, means whereby they master crankshaft holds the wheel in abrading contact with a crank pin during eccentric revolutionthereof, means for rotating the, wheel tqfgrind-:fthe pimp-and means for revolving the wheel axiseccentrically during grinding. l

7. A crankshaft grinding machine comprising means lfor supporting and rotating'a crankshaft about the axis of litsy bearings, a plurality of grinding wheels, means for` holding the wheels with their end plane faces in abrading contact with the crank pins during eccentric revolution thereof, means-for rotating the wheels, means for revolving the wheels eccentrically relative to their axes during grinding and mechanism for moving thel wheel simultaneously towards and 10. crankshaft grinding machine according to claim 3 comprising a rotatable grinding wheel shaft, a hollow shaft eccentrically surrounding said shaft and supporting the samel and a motor directly connected to the wheel shaft and indirectly connected to rotate the hollow shaft.

11. A. crankshaft grinding machine according to claim 7 which comprises a. common movable support for all of the grinding wheels and fluid pressure mechanism for moving said support. 12. A crankshaft grinding machine comprising means for supporting and rotating a crankshaft, a set of supporting shafts and grinding wheels thereon having theirl flat faces arranged to grind thecrank'pins, a motor for each wheel, means for connecting each grinding wheel shaft directly to the motor shaft, a rotatable hollow shaft eccentrically supporting each wheel shaft,

means connected to each motor for rotating the 

